A skier of mass 60 kg is pulled from rest up a snowy slope by a tow rope. The skier finishes 5.0 m higher and is moving at 4.0 m/s. The tow rope transfers 4000 J mechanically to the skier. Use g=10 N/kgg=10\ \mathrm{N/kg}g=10 N/kg. How much energy is transferred to thermal stores during this journey?
520 J520\ \mathrm{J}520 J
1000 J1000\ \mathrm{J}1000 J
3000 J3000\ \mathrm{J}3000 J
480 J480\ \mathrm{J}480 J